Electric indicating means



June 10, 1941. E. NOTHE ELECTRIC INDICATING MEANS Filed Sept. 1, 1938 llOMACrNET/C INVENTOR. BY %H%( 2 q T o R ix III //7 associated with saldcore.

s Patented June 10, 1941 ELECTRIC INDICATING MEANS Erich Niithe,Berlin-Spandau, Germany, assig'nor to Siemens Apparate und MaschinenGesell- Schaft mit beschriinkter Haftung, Berlin, Germany, a corporationof Germany Application September 1, 1938, Serial'No. 228,068

- In Germany September 25, 1937 4 Claims. (01.177-329) This inventionrelates to electric indicating means and more particularly toelectromagnetically actuated rotary indicators for use in asso ciat-ionwith, for example, the instruments upon the dashboard of a vehicle suchas an aircraft.

One of the objects of the present invention is to provide novel meansfor indicating when an electric current is fiowing in an electric'leador v flowing to an electrically actuated instrument.

Another' object of the invention-is to provide a novel indicator havinga high sensitivity but capable of withstanding vibrations.

Another object is to provide a novel indicator having small dimensions.

A further object is to provide a novel electromagnetic device of theabove character having a low magnetic leakage flux whereby adjacentinstruments are-safe from the disturbing efiects caused by such leakage.

The above and further objects and novel features will more fully appearfrom the following detailed description when the same is read inconnection with the accompanying drawing. It is to be expresslyunderstood, however, that the drawings are for purposes of illustrationonly and are not intended as a definition of the limits of theinvention, reference for this latter purpose beinghad tothe appendedclaims.

In the drawing, wherein like reference characters refer to like partsthroughout the several viewsz" Fig. 1 is a plan view, with a top coverremoved,

showing one embodiment of the present invention;

Fig. 2 is a side elevation in section taken substantially along line'2-2'of Figure 1;

plan view of the -above embodiment;

net. The. apparatus comprises a metallic coremember which-is surroundedby an exciter coil. An angularly shiftable armature is mounted upon saidcore adjacent suitable pole shoes which are The armature iscoaxial withthe coil and so arranged with respect to the core and pole shoes thatthe lines of force existing between "the core; armature and pole shoesare substantially perpendicular to the coil axis. v

In the form shown in Fig. 2,,a cylindrical case III of a magneticmaterial is provided having upon the upper edge 10o thereof and formedintegrally therewith, a pair of upwardly extending pole piecesI Ilb andI00. Pole pieces I01) and IIlc are diametrically opposed. I

An exciter coil II lies flat upon and is attached to the bottom of caseI 0 and is connected in the circuit of an electric lead wherein it isdesired to determine when a current is flowing.

From the bottom of case I0 a central core I2 extends above coil I I. Thecore is provided at the extremity thereof with a recess. IZa for anon-magnetic bearing portion I3 in which there is rotatably supported ashaft I4 which is coaxial with said core. Upon a hub I5 which is mountedupon said shaft there is mounted a flat non-- magnetic. indicatorportion II; which supports above the coil II an armature I1. IndicatorI6 is in the shape of a cross having four arms comprising sectors ofcircles. The indicator is to be read inassociation with a face plate tobe later described. Armature I1 is in theform of a fiat ring portionhaving an inner annular flange I'Ia,

and a pair of arms Ill) and Ho extending outwardly from, and integralwith, said ring portion. In order to increase the attraction between thepole pieces and the armature, arms Nb and Ho are provided atthe outeredges thereof with flange portions I8 and I9, respectively, said por-.

tions being movable adjacent the pole pieces 10b and IE0. The flangeportions I8 and I9 vare tapered, i. e., they are in the shape of theouter surface of a sector of a cylinder formed between two intersectingplanes which form an acute angle with one another. This flange formationmakes it possible'for a progressively increasing flange area to moveadjacent each pole piece as the armature is angularly displaced from itsinitial position: Consequently, the motor action or the attraction bythe pole pieces will correspondingly increase with the angulardisplacement of and shape of the indicator portion I6. A'central bore insaid face plate serves as an upper bearing for the armature shaft I4.

In order that the angularly shiftable armature I! may be yieldinglyurged in a predetermined dithereof to hub l5 and bearing l3. When coilII is de-energized, spring 23 urges the armature against a limit-stopcomprising an extremity 24a of a member 24.- The member 24 isconstituted by a strip of non-magnetic material which conforms to thecurvature of the inner surface of container I0. Member 24 is rigidlyheld in place' by means of a screw 25 (Fig. 1). An opposite extremity24b of said strip serves as an abut- .able means better shown in Fig. 4,a more positive magnetic attraction may be obtained which will furtherreduce the sensitiveness of the device to vibrations and to suddenshock. Such a metal portion 26 is mounted adjacent the extremity 24b oflimit-stop 24 (Fig. 1). The armature is magnetically tightly gripped byportion 26 when the indicator is in the on" position.

The visible portions of the indicator l6 are coated with a luminoussubstance, for example a phosphorescent paint or some radioactivematerial, in order to render these portions conspicuous.

In operation,-coil II is energized by connection to a suitable energysource (not shown). Armature I! is situated between the pole pieces loband I 00 and the central core 12 in such a manner that thelines of forcerun substantially perpendicular to the axis of the electromagneticdevice, i. e. the axis of coil II and core I 2. The armatureis'attracted by said pole pieces and thus is angularly shifted againstthe pressure of spring 23 until flanges l8 and I9 are opposite the poleslflb and H10, respectively, at which time the armature will engage theportion 26 of limitstop 24b. The cross-shaped indicator I6 moves withthe armature from the initial or oil position,when the indicator armsare covered by plate 21, to the on position where said arms are visiblethrough perforations 22.

There is thus provided a novel indicating device wherein the movingparts are angularly but not longitudinally shiftable. The apparatustherefore is not sensitive to the ordinary longitudinal vibrations whichoccur, for example, aboard aircraft. When the electromagnet isenergized, the lines of force are required to bridge only very shortgaps. Consequently, the stray or leakage flux is reduced'to a minimumand the device will not electrically disturb such gauges, measuringnearby. The indicator is of small size and is adapted to fit within asmall bore which may be drilled in a dashboard or panel.

departing'from the spirit and scope of the inapparatus and compasses,etc., which are located vention as the same will now be understood bythose skilled in the art. For a definition oi the limits of theinvention, reference.will be had primarily to the appended claims.

What is claimed is:

Lin 9. signal device of the current indicator type, the combination witha pair of pole pieces, of a central core, a coil coaxial with said core,an armature having depending means on its, outer periphery, non-magneticmeans for mounting said armature for angular movement between zero andfull scale positions on a shaft, said shaft being coaxial with. andsupported by said core, means comprising a limit-stop provided with endsdefining contact surfaces for said armature whereby during angularmovement thereof the armature contacts one of said surfaces in its zeroposition and the other of said surfaces. at its full scale position, onecontact surface only of said limit-stop means comprising a magneticmember, and means for yieldingly urging said armature against onesurface of said limit-stop.

2. In a signal device a central core, an armature coaxial therewith,means supporting said armature upon said core for angular movementthereon between a zero and full scale position, an indicator memberrigidly secured to said faces cooperates with said armature at its full.

scale position, the latter of said surfaces being provided with magneticmeans.

3. In an instrument of the current indicator typ the combination with apair of pole pieces, of a central core, a coil coaxial with said core,an armatureinsulated from and mounted for angular movement upon saidcore between a zero and full scale position, and means comprising alimit-stop provided with ends defining contact surfaces for saidarmature whereby during angular movement thereof the armature contactsone of said ends in its zero position and the other of said ends at itsfull scale position, one of said ends comprising a magnetic memberconnected with one of said pole pieces.

4. In an instrument of the current indicator type, the combination witha pair of pole pieces of a central core, a coil coaxial with said core,

an armature insulated from and mounted for .angular movement upon. saidcore between a zero and full scaleposition, said armature comprising aring portionprovided with depending flanges surrounding said core andoutwardly extendin arm members having tapered flanges at the outwardends thereof associated with said pole pieces, and means comprising alimit-stop provided with ends defining contact surfaces for saidarmature whereby during angular movement thereof the armature contactsone of said ends in its zero position and the other of saidends at itsfull scale position, one of said ends comprising a magnetic membersecured with one of said pole pieces.

ERICH Nonin-

